Package org.terrier.matching.tsms

Class TermInFieldModifier

java.lang.Object

org.terrier.matching.models.WeightingModel

org.terrier.matching.tsms.TermInFieldModifier

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, Model, IndexConfigurable

public class TermInFieldModifier
extends WeightingModel
implements IndexConfigurable

Resets the scores of documents according to whether a term appears in a given set of fields. This class implements the TermScoreModifier interface.

Author:

Vassilis Plachouras

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
protected java.lang.String	field	The fields that a query term should appear in.
protected Index	index
protected boolean	requirement	The requirement.

Fields inherited from class org.terrier.matching.models.WeightingModel

averageDocumentLength, c, cs, documentFrequency, es, i, keyFrequency, numberOfDocuments, numberOfPointers, numberOfPostings, numberOfTokens, numberOfUniqueTerms, rq, termFrequency

Constructor Summary

Constructors

Constructor	Description
TermInFieldModifier(java.lang.String _field)	Constructs an instance of a TermInFieldModifier given a field that the corresponding query term should appear in.
TermInFieldModifier(java.lang.String _field, boolean req)	Constructs an instance of a TermInFieldModifier given a field that the corresponding query term should appear in.

Method Summary

Modifier and Type	Method	Description
java.lang.String	getInfo()	Returns the name of the model.
java.lang.String	getName()	Returns the name of the class and whether the query term is required.
void	prepare()	prepare
double	score(double tf, double docLength)	This method provides the contract for implementing weighting models.
double	score(Posting _p)	Returns score
void	setIndex(Index i)	Tell the implementer which Index object it is associated with.

Methods inherited from class org.terrier.matching.models.WeightingModel

clone, getOverflowed, getParameter, setCollectionStatistics, setEntryStatistics, setKeyFrequency, setParameter, setRequest

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

index

protected transient Index index

field

protected java.lang.String field

The fields that a query term should appear in.

requirement

protected boolean requirement

The requirement. By default it is true.

Constructor Detail

TermInFieldModifier

public TermInFieldModifier(java.lang.String _field)

Constructs an instance of a TermInFieldModifier given a field that the corresponding query term should appear in.

Parameters:

_field - String a field

TermInFieldModifier

public TermInFieldModifier(java.lang.String _field,
                           boolean req)

Constructs an instance of a TermInFieldModifier given a field that the corresponding query term should appear in.

Parameters:

_field - String a field

req - boolean the requirement for this field. If req is true, then the term is required to appear in the field (this is the default behaviour), otherwise the term should not appear in the field.

Method Detail

prepare

public void prepare()

prepare

Overrides:

prepare in class WeightingModel

score

public double score(Posting _p)

Returns score

Overrides:

score in class WeightingModel

Returns:

score

getName

public java.lang.String getName()

Returns the name of the class and whether the query term is required.

getInfo

public java.lang.String getInfo()

Description copied from class: WeightingModel

Returns the name of the model.

Specified by:

getInfo in interface Model

Specified by:

getInfo in class WeightingModel

Returns:

java.lang.String

score

public double score(double tf,
                    double docLength)

Description copied from class: WeightingModel

This method provides the contract for implementing weighting models.

Specified by:

score in class WeightingModel

Parameters:

tf - The term frequency in the document

docLength - the document's length

Returns:

the score assigned to a document with the given tf and docLength, and other preset parameters

setIndex

public void setIndex(Index i)

Tell the implementer which Index object it is associated with.

Specified by:

setIndex in interface IndexConfigurable

Parameters:

i - Index object to use